Empty row responses break infinite row model grids

[NiklasKappel]

MWE

import numpy as np
import pandas as pd
from dash import Dash, Input, Output, callback, ctx, html
from dash_ag_grid import AgGrid

data = df = pd.DataFrame(
    {
        "id": range(1000),
        "value": np.random.rand(1000),
    }
)

clear_button = html.Button("Clear", id="clear")
reset_button = html.Button("Reset")

grid = AgGrid(
    columnDefs=[
        {"field": "id"},
        {"field": "value"},
    ],
    getRowId="params.data.id",
    rowModelType="infinite",
)


@callback(
    Output(grid, "getRowsResponse"),
    Input(grid, "getRowsRequest"),
    Input(clear_button, "n_clicks"),
    Input(reset_button, "n_clicks"),
    prevent_initial_call=True,
)
def update_rfq_grid_rows(
    request,
    n_clicks_clear,
    n_clicks_reset,
):
    if ctx.triggered_id == "clear":
        response = {
            "rowData": [],
            "rowCount": 0,
        }
        print(response)
        return response

    if request is None:
        partial_df = data.head(100)
    else:
        partial_df = data.iloc[request["startRow"] : request["endRow"]]

    response = {
        "rowData": partial_df.to_dict("records"),
        "rowCount": len(data.index),
    }
    print(response)
    return response


app = Dash()
app.layout = html.Div(
    children=[
        clear_button,
        reset_button,
        grid,
    ]
)

if __name__ == "__main__":
    app.run(debug=True)

What I do

1. Run the app.
2. Click the clear button.
3. Click the reset button.

What I expect

After clicking the reset button, the grid should display data.

What I get

After clicking the reset button, the grid stays empty.

Why this is relevant

The two buttons mock my business logic. In my actual use case, the user can enter filter values into a form and click a button to filter the data in the grid. Some combinations of filter values are not fulfilled by any row in the dataset. As a result, the row response is empty. This is emulated by the clear button. Changing the filter settings should allow the user to fill the grid again with data. This is emulated by the reset button.

Environment

> pip freeze
blinker==1.9.0
certifi==2026.2.25
charset-normalizer==3.4.4
click==8.3.1
colorama==0.4.6
dash==4.0.0
dash_ag_grid==33.3.3
Flask==3.1.3
idna==3.11
importlib_metadata==8.7.1
itsdangerous==2.2.0
Jinja2==3.1.6
MarkupSafe==3.0.3
narwhals==2.17.0
nest-asyncio==1.6.0
numpy==2.2.6
packaging==26.0
pandas==2.3.3
plotly==6.5.2
python-dateutil==2.9.0.post0
pytz==2025.2
requests==2.32.5
retrying==1.4.2
six==1.17.0
typing_extensions==4.15.0
tzdata==2025.3
urllib3==2.6.3
Werkzeug==3.1.6
zipp==3.23.0

[BSd3v]

Hello @NiklasKappel

Check here and see if this helps your use-case.

#59

Essentially, never return a 0 value for the counts.

[NiklasKappel]

Thank you! Returning len(df.index) or 1 as "rowCount" works for me. I had to adjust my cell formatting function though, so that the single rendered row appears empty, and does not contain NaNs etc.